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[broadstairs]

Well this is a tad embarrassing to say (in light of my comments elsewhere about homeplugs) but I think I have found the cause of my horrendous levels of CRCs and FECs over the very recent past. Having turned off my homeplugs it made no difference to the error rate so I decided to actually turn the sockets off AND remove the homeplugs from the sockets and so far after about 36 hours the horrendous error rate has not returned (hence my comment elsewhere about using wireless on my F1000).

Now my homeplugs are a set of TP_Link TL-WPA4220 wi-fi extenders and to be honest I did not expect to have to actually unplug them for the interference go away. My experience with these from when I first installed them was pretty good and I did not see the errors I have been having recently. Prior to installing these wi-fi adapters I had a pair of simple Lan extenders from another manufacturer (cant remember which right now) with a wireless AP at the remote end and again did not have the errors I have seen recently.

So my conclusion is that these TP-Link adapters have started to fail for some reason or other and since they are less than 12 months old I will try to return them for replacement and to allow them to be tested.

Stuart

Just to say my ES per day have gone from 15715 2 days ago to 255 today..... with FECs dropping from 6,000,000 per day to about 173,000 today and CRCs from 98,000 to 1360 but as I said I had to actually unplug the adapters merely turning them off was NOT good enough.

[kitz]

Thats a heck of a drop..  its good that youve found out what was causing it, but not good at the culprit.

btw.. do I recall that HPsauce may have said something recently about him noticing some interference regardless or not whether the offending item was plugged in and even when switched off still generated errors on the line. ? ?

[burakkucat]

I wonder if the "on/off" switch of the devices just isolates the low voltage side of the inbuilt PSU, leaving the mains side of the PSU still energised? 

[broadstairs]

I wonder if the "on/off" switch of the devices just isolates the low voltage side of the inbuilt PSU, leaving the mains side of the PSU still energised? 

I was talking about the on/off switch on the power socket. The TP-Link kit I have has no on/off switch on it.

Stuart

[burakkucat]

Well that is very peculiar! (And interesting.    ) At the moment, I am unable to rationalise your observations . . . 

[sevenlayermuddle]

Is the earth pin on these devices metal, or plastic?

As far as I know, UK sockets do not have to be double pole switched.  If double pole switched then it is quite baffling, but if single pole, then the neutral remains connected when switched off and, if earth pin is also connected then currents may flow from earth to neutral, passing through the home plug's internals.  If that were the case then I'd be inclined to speculate that the effect being observed is of exacerbating effects of some noise that is already present in the mains wiring, rather than generated within the home plugs.   

But I agree it is an interesting problem that would be nice to properly understand.

[broadstairs]

Is the earth pin on these devices metal, or plastic?

On the TP-Link in question it is a metal earth pin so your theory is possible although the current would have to be quite small as we have an ELCB in the house which is quite sensitive. I'll dig out my other set which from memory is a Devolo (not wireless at remote end) and see what the earth pin is on that. Dont remember seeing those kind of errors with the Devolos.

Stuart

[sevenlayermuddle]

Is the earth pin on these devices metal, or plastic?

On the TP-Link in question it is a metal earth pin so your theory is possible although the current would have to be quite small as we have an ELCB in the house which is quite sensitive. I'll dig out my other set which from memory is a Devolo (not wireless at remote end) and see what the earth pin is on that. Dont remember seeing those kind of errors with the Devolos.

Stuart

Low current would not be an obstacle.   

I actually think most such devices are current sensing these days (RCDs), and typically trip at a generous 30mA or so.    That's well below the levels that usually prove lethal but if, say, the earth-neutral imbalance is a mere 10V, it would be enough to supply a 300mW radio transmitter, sufficient to cover provide reliable reception several miles away, whilst completely overwhelming low level signals close to the source.

The type of electricity supply may also be relevant.   ISTR some supplies effectively have neutral and earth pinned to one another at intervals along the line and again at the entry point, whilst others have true floating neutral.   Experts on supply may correct me on that.

But I do emphasise mine is just one theory, that may prove utter tosh.   I will be fascinated to see what other theories might emerge to explain this fascinating situation.   

[NewtronStar]

Well this is a tad embarrassing to say (in light of my comments elsewhere about homeplugs) but I think I have found the cause of my horrendous levels of CRCs and FECs over the very recent past. Having turned off my homeplugs it made no difference to the error rate so I decided to actually turn the sockets off AND remove the homeplugs from the sockets and so far after about 36 hours the horrendous error rate has not returned (hence my comment elsewhere about using wireless on my F1000).

My quote from that other thread ->
once the powerline adapters were taken offline they fell back to 250 - 1000 per minute.
meaning both PLA's pairs physically removed from the power socket.

[burakkucat]

I can confirm that the earth and neutral of my electricity supply are linked together, along with the armouring of the supply cable, at the main fuse.

As I understand it, my supply comes via a "delta-star" transformer, where the neutral (taken from the centre of the star) is also connected to earth. The photograph of the supply transformer, attached below, is dated December 2012.

[broadstairs]

I've been thinking about this and I think the problem is that the interference may be being injected not via the mains and PSUs but via the LAN cable plugged into the router. In fact from memory I think the situation of the absolutely horrendous errors started when I moved the LAN cable from my 8-way gigabit network switch into the F1000 router. Also I am convinced that the devices did not seem to cause problems when first installed and connected to the switch, trouble is that I only keep a limited number of days snapshots from DSLStats. Since during all this time I did not have any problems with re-syncs caused by the errors I may try plugging the TP-Links back in with initially no LAN cable and see if the errors re-appear. If not then I'll put the LAN cable back in but into the switch first and see what happens.

Stuart

[roseway]

I can confirm that the earth and neutral of my electricity supply are linked together, along with the armouring of the supply cable, at the main fuse.

As I understand it, my supply comes via a "delta-star" transformer, where the neutral (taken from the centre of the star) is also connected to earth. The photograph of the supply transformer, attached below, is dated December 2012.

I forget what the proper terms are now, but as I understand things it's now normal to use the neutral lead as the domestic earth on new installations and upgrades, but older installations (*) require a separate earth rod in the ground outside the premises, with the neutral being earthed some distance away. In the latter case there can be a significant voltage difference between neutral and earth.

* Even older installations may have an earth supplied as part of the incoming power cable.

[NewtronStar]

I may try plugging the TP-Links back in with initially no LAN cable and see if the errors re-appear. If not then I'll put the LAN cable back in but into the switch first and see what happens.
Stuart

Try it broadstairs, I did the same thing as your about to 7 months and found the interference from PLA was still getting through to HG612, so that meens the interference is getting into the modems PSU via the mains and then into modems circuitry.

Let's hope you don't get the same result as me.

[broadstairs]

Well so far since plugging back in my TP-Link adapters turned on but without a LAN cable to connect it up my error rates are not significantly different. I will leave it like this now well into the evening or perhaps till tomorrow morning before I plug in the LAN cable, and initially I will connect it to my V7 Gigabit Switch and not directly to the F1000 and again leave it for some hours to see what happens. Frankly I dont expect (from past experience) to see the horrendous errors until the LAN cable is connected to the F1000 but we shall see.

Stuart

[broadstairs]

Well over the passed couple of days I can honestly say my error rate has not been unreasonable since plugging back in the TP-Link kit - a touch higher but not significantly higher. So earlier today I plugged in the LAN cable and put it into the F1000. Now for the passed few hours once again the error rate has not been unreasonable, so now to see what happens with my Samsung Tab3 7inch connected to the wireless AP on the TP-Link. I'll leave it on for at least 24 hours but it is somewhat strange that as soon as I unplugged the TP-Link kit the error rate dropped but now I'm not seeing the same issue at all. The only thing is I cannot be sure I am using the same LAN cable as I have all spares in the same box and most are the same colour!

So we will wait and see....

Stuart